The invention relates generally to an apparatus for in situ radiotherapy of a patient with a radioisotope and more particularly to a guide tube apparatus wherein the tube has a releasable anchor. The invention also relates to a multiple catheter apparatus wherein the catheters extend through a common bushing.
It has been found that certain malignancies which are inoperable or nonresectable may advantageously be treated through radiotherapy techniques wherein radioactive objects or pellets are implanted within or in the vicinity of a tumor mass or in some cases at a site from which a tumor has been removed and for which there is concern that malignant cells may have spread. One of the drawbacks which health care professionals have found with such a treatment modality relates to the fact that in order that they may be left within the patient, the radioisotopes, of necessity, must be relatively low intensity emitters. Another drawback is that such radioactive sources must not only be surgically implanted within the patient but also be extracted surgically.
In an improved version of this technique as described in the aforementioned copending application localized radioactive sources are positioned in proximity to tumor bodies and the like for brief precise time intervals. Typically a guide tube, such as a hollow needle, a catheter or a lumen, is implanted within a tumor mass and exits through the skin of the patient. A source wire having a radioisotope positioned therein is fed into the guide tube and brought into proximity to the tumor mass. Typically the radioactive portion of the wire is composed of an iridium 192 element about 5 millimeters in length which provides highly localized intense gamma radiation to a relatively small volume of tissue. By positioning a number of such guide tubes within a tumor mass and adjusting the longitudinal positions of the radioactive sources within the guide tubes or catheters the entire tumor mass can be exposed to high intensity radiation for a short period of time with little damage to surrounding tissue.
In order to carry out this type of treatment it is, of course, necessary that the radioactive portions of the wires be precisely positioned in relation to the tumors, and ideally no healthy tissue outside the tumor should be exposed to radiation. As a result, errors in the placement of the radioisotopes within the guide tubes are to be avoided.
One of the prior art methods which has been found to provide the requisite precise positioning employs catheters extending into the patient's body, into a portion of the patient's anatomy which is to be treated and then out of the body at points where the catheters are closed and anchored. In the prior art treatment systems typically there are multiple punctures extending into the body, through the organ to be treated and out of body on the other side where anchoring devices hold the exposed catheter ends. The guide tubes extending through the punctures are typically anchored at both ends causing them to be translationally fixed with respect to the tumor. As a result, once it is known how far the various portions of the tumor are located from the entry points of the guide tubes, the relationship between the catheters and the tumor will not change while the catheters remain in the patient. The use of this system, however, suffers from the drawback that multiple openings are made in the patient's body. Each of the openings is a potential site for entry of infectious agents and will remain open for several days while the radioisotope treatment is carried out.
In other instances where tumors of the prostate, bowel and the like are to be treated there is no convenient way of anchoring the proximal ends of the catheters, which typically extend slightly past the tumor site. As a result, due to the patient moving, the guide tubes may slide out of the patient and at the very least the extent to which the guide tubes extend into and out of the tumor mass would have to be recalibrated each time the radioisotopes are replaced in the guide tubes for treatment.